pH meter



FIG. 1 is a top, front and right side perspective view of a pH meter showing my new design;

FIG. 2 is a top plan view;

FIG. 3 is a left side perspective view;

FIG. 4 is a bottom plan view;

FIG. 5 is a right side perspective view;

FIG. 6 is a front elevational view; and

FIG. 7 is a rear elevational view thereof. 

The ornamental design for a pH meter, as shown. 